The present invention relates to an improvement in a vertical or lateral series of four slips.
In order that the payment of a tax or payment for an article bought on time may be made at the window of a post office or a bank, it is a common practice that a person to whom money is to be paid sends a lateral series of four slips to a person by whom the payment should be made. In the case of payment for an article bought on time, the lateral series of four slips consists of a notification for payment, a payment slip, a credit slip, and a receipt. In the case of payment of a tax, it consists of a receipt, a statement of payment, a notice of the tax paid, and a reminder.
In order to mail such a lateral series of four slips, it has been a common practice to fold it in four and put it in an envelope. This is an uneconomical operation.